Defrosting means for refrigerating apparatus



Oct. 12, 1937. c. A. RODMAN DEFROSTING MEANS FOR REFRIGERATING APPARATUSFiled May 51, 1935 INVENTOR ATTORNEY Patented Oct, 12,1937

nnmos'rmq MEANS non arrm'ru Badman, Detroit, Mich, assignor to John B.Tanner Clarence A.

PATENT OFFICE.

gnramnmmc 'Aiipiicauon May 31, 1935, Serial No. 24,382

This invention relates to air conditioning and i refrigerating systems.Its' principal object is to provide a simple, effective means forquickly and economically defrosting the expansion or cooling 5 coils ofsuch a system.

In the use of refrigerating means in the apparatus when forcedcirculation of air is provided, such for example as in my airconditioning apparatus shown, described and claimed in my Patent No.2,009,817, issued July 30, 1935, for

Refrigerating and dispensing apparatus, and in other devices of thecharacter of the latter example, quick and effective efrosting is highlydesirable. This application is a continuation in part of the aforesaidpatent.

In any such arrangement where air is circulated in a return bendthrough-a series of ex: pansion tube coils, partitions are utilized, andan object of this invention is to so construct such partitions that theymay be provided. with heating means which may quickly raise thetemperature of these partitions and thus cause the air to pass incontact with heating surfaces as it passes over the cooling elementswhich during this heating, are defrosted and preferably shut off fromthe refrigerant, that is, the'flowof refrigerant is discontinued duringthe defrosting intervals.

Further objects include the simple emcient construction of such heatingand defrosting 3 means, providing for a cheap assembly of it with thecooling unit.

A more specific object is tois'o construct walls or partitions in acooling unit that I may elec- 'trically heat the same for the purpose ofde- 35. frosting.

Other objects and advantages will become more apparent in the followingdescription which relates to the accompanying drawing in which:

Fig.1 is a sectional view illustrating a condensing or expansion type ofrefrigerating device through which air is passed by forced circulation.

Fig. 2 is a side elevation of-rny evaporator unit showing the partitionsadapted. to be heated therein. I 45 Fig. 3 isa sectional line 3-3 of.Fig. 2.

In the drawing Fig. 1 shows a structure similar to that of Fig. 1 of myprior application'No. 731,657, above referred to and to which referencemay be had for more detailed description 0! its operation.

For convenience we will here again briefly describe the constructionshown as illustrative of any use or embodiment of the present invention.

I indicates a suitable casing having insulation plan of the same on the.thence to a storage tank unit is disconnected from t, surrounding ametallic chamber l0 enclosing theexpansion or cooling coils ii of arefrigerating unit. A suitable compressor and driving mechanism isindicated at l8 and driven by a motor designated 20. Fromthe coil Ii tothe 5 compressor is a return passage or tube 22. From the compressor theliquid refrigerant passes through condenser coils indicated at 24 andfrom which it passes through a tube 21 to a suitable expansion valve 10connected with the expansion and refrigerating coils l5.

The coils are divided by partitions 32 below which is an opening 33, airbeing impelled by a fan indicated at 40 of the Sirroco" type and Illdriven by a motor as shown at 42. The air passes upwardly from the fanthrough a passage 44 to the chamber (not shown) to be cooled, and thencereturned to the casing I0, thus, the refrigerated air is circulated overany food or other 20 material to be refrigerated or cooled.

While in the operation of suclra system, I have, by the use of speciallyconstructed expansion valves effected a high degree of control of thehumidity as described in 'my copending applica- 25 tion, referred to,defrosting becomes necessary or at least desirable at intervals and itis essential and economical to effect quickly.

In the use of such cooling coils for various refrigerating systems it iswell known that such requirements for defrosting afford a diillculty, inthat the foods or other materials .being preserved, must during thedefrosting period, be subjected to warm air over long periods, while thefrost and ice accumulation on the coils slowly melts. Wherever possible,of course the refrigerator,

the preservation chamber, but frequently this is not possible and inmost instances the entire apparatus must be the defrosting most emptiedof its foods and other material for such defrosting.

By the present invention I am enabled however, to completely defrost andin fact effectively dry the refrigerating coils in a very few minutes. 4

My-preferred method is that illustrated in Figs. 2 and 3, in which Ihave shown the cooling unit as comprising the plurality of loopedportions of the tube I, having parallel reaches ll connected by returnbends 52. The parallel portions being provided with spaced fins or heatradiating members 5|, the parallel portions and radiating fins beinghoused in a suitable box like case I. I

Intheupper righthand corner ofthiscaseil indicated a fan housingrepresented by the broken lines 62 and line 63 indicates an outletpassage.

' The casing isshown as divided into three sections by the partitions land I2, each of which stops short of reaching the full length of thecasing to leave passages for air as indicated by the broken line, arrowsi4 and 15. The air inlet opening 16 is indicated by the broken'linearrows at the lower left of the casing.

These partitions ill and I2 are preferably of a hollow nature withinwhich is included heating elements. Any kind of heating element may be Vused, as for example, the resistance unit in an '"electric iron, theelement being supported by. a

sheet of mica or like material to which the element is attached, andthen'after insulating the indicated at $2.

-Obviously 'in the normal cooling operation of the coils the heatingelements are idle but when it is desired to defrost, the conditions ofthe merchandise to be refrigerated having beensuitably taken care of, asby shutting off circulation thereto or by removing,'if desired, currentis then supplied to the heating elements 80 by closing suit ableswitches, one of which is indicated at 85. The fan is continued inoperation and the heat of the surfaces of the partitions l0 and I2,coming in contact with the air passing along both sides of eachpartition and also in contact with the reaches 50 of the coils transfersthe heat thus delivered to the surfaces of the coils and very rapidlyeffects melting and evaporation. The de frosting is thus accomplished ina few minutes time. The circuit through the heating elements is thenopened and the refrigerating may be immediately resumed.

While. I have described'the heating means as electrical, obviously otherheating media may be used where conveniently available. For example, hotwater or steam may be circulated through a hollow partition or throughtubes built into the partitions or wall surfaces.

Other modifications, such as the providing of heating elements inthe-walls of the casing, for

process cooling unit, may be provided with electric or other heatingunits.

Having thus described my invention, I claim:

1. The combination with a cooling coil of a refrigerating apparatus, ofa casing embracing portions of said coil and having wall membersefiecting a circuitous passage therein, means for forcibly circulatingair in said passage and means for heating a wall surface of the passage.

2. The combination with the expansion coil of a. refrigerating apparatusof a casing embracing a plurality of reaches of said coil, a partitiondividing the casing for a portion of the'distance across one wallthereof to another, inlet and outi let air orifices, a fan for moving'air through said passage, said partition having electric heatingelements therein adapted to facilitate defrosting of the coil.

3. In a refrigerating system of the compression-expansion type, thecombination with an evaporator having parallel reaches, of a supportingmember for said reaches and forming a passageway for air to becirculated therethrou gh,

means connected to said reaches for causing heat and cold transmissionthereto, a means for causing a circuitouspassage of air through saidevaporator, and a means associated with said evaporator for heating saidlast mentioned means.

4. The combination with the expansion coil of a refrigerating apparatus,of a casing embracing a plurality of reaches of said coil and forming anair passageway, a means providing a circuitous air passageway, saidmeans having electric heating elements therein adapted to defrost saidreaches of said coil, and a fan for moving air through said passageway.

5. The combination with the expansion coil of a refrigerating apparatus,of a casing embracing a plurality of reaches of said "coil and'formingan air passageway, a means providing a circuitous air passageway, saidmeans having electric heating elements therein adapted to defrost, meansfor the transfer of heat and cold to the reaches of said coil, and a fanfor movingair through said passageway.

CLARENCE A. R ODMAN.

example, the vertical walls of the case 60 of the

